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R Huang

Publications and source records attributed to R Huang.

At least 55 records · Page 3Linked to original sources
PubMed2001

Birth weight prediction by three-dimensional ultrasonography: fractional limb volume.

OBJECTIVE: To introduce fractional limb volume as a new ultrasonographic parameter, validate reliability of fractional limb volume measurements, develop new birth weight prediction models, and examine their practical utility for estimating fetal weight during late pregnancy. METHODS: Healthy late-third-trimester fetuses were prospectively scanned by two- and three-dimensional ultrasonography within 4 days of delivery. Volume data sets were subsequently used to extract several standard ultrasonographic measurements. Fractional limb volumes of the upper arm and thigh were based on 50% of diaphyseal bone length. Intraclass correlation was used to analyze interobserver and intraobserver reliability of fractional limb volume measurements. Several weight prediction models were developed by linear regression analysis. New prediction models were prospectively compared with the Hadlock formula in 30 healthy late-third-trimester fetuses. RESULTS: One hundred fetuses were scanned at a mean +/- SD menstrual age of 39.2 +/- 1.2 weeks. Intraclass correlation indicated a significant degree of interobserver and intraobserver reliability for fractional thigh volume. Fractional thigh volume (r = 0.86), fractional upper arm volume (r = 0.83), abdominal circumference (r = 0.83), and midthigh circumference (r = 0.82) were most highly correlated with birth weight. The best prediction model (abdominal circumference and fractional thigh volume) gave weight estimates that deviated from actual birth weight by -0.025% +/- 7.8%. For late-third-trimester fetuses, the Hadlock model yielded errors of 9.0% +/- 9.0%. Prospective testing confirmed superior performance of the new prediction model, which gave accuracy of 2.3% +/- 6.6% (Hadlock method, 8.4% +/- 8.7%). It correctly predicted 20 of 30 birth weights to within 5% of actual weight. By comparison, the Hadlock model predicted only 6 of 30 birth weights to within 5% of actual weight. CONCLUSIONS: A new birth weight prediction model, based on fractional thigh volume and abdominal circumference, is reliable during the late third trimester. It provides a means for including soft tissue evaluation for birth weight prediction. This rapid technique avoids technical limitations that currently hinder the practical implementation of three-dimensional ultrasonography for estimating birth weight.

Birth Weight↗
PubMed2001

[Complications in laparoscopic gynecologic surgery: analysis of 34 cases].

OBJECTIVE: To investigate retrospectively the complication rate of gynecological laparoscopies at Peking union medical college (PUMC) hospital over 6-year period. METHODS: 1,769 laparoscopic surgeries were carried out from Jan. 1994 through Oct. 1999. The procedures included 1,421 adnexal surgeries, 52 myomectomies and 296 laparoscopic assisted vaginal hysterectomy (LAVH). Complication was defined as an event that had modified the usual course of the procedure or of the postoperative period. RESULTS: Complications occurred in 34 cases, the overall complication rate was 1.9%. Unintended laparotomies occurred in 6 cases (0.3%). Complication rate was 0.9%, 1.9% and 6.8% in adnexal surgeries, myomectomies and LAVH respectively. 12 (35.3%) complications related to puncture and pneumoperitoneum, including five severe emphysema, 7 injuries to epigastric blood vessels of abdominal wall and omental blood vessel, this figure represented 35.3% of all complications of this series. 5 (14.7%) intraoperative, complications occurred during the laparoscopic surgery (3 severe bleedings, 1 bladder injury and 1 skin burn of leg related to the electrode plate), laparotomy was required in 4 of these cases. 17 (50.0%) complications occurred during postoperative stage: 2 intraperitoneal hemorrhages needing re-laparotomy, 2 bowel complications, 4 nerve paresis and 9 febrile morbidities. CONCLUSIONS: In our experience, operative gynecologic laparoscopy is associated with acceptable morbidity rate, but can not be overlooked. Complications seems related to advanced procedures such as LAVH.

Female↗
PubMed2001

Laparoscopic myomectomy.

OBJECTIVE: To investigate the indications, surgical techniques and complications of laparoscopic myomectomy. MATERIALS AND METHODS: A retrospective study was carried out in 74 patients with fibroids > 3 cm from March, 1995 until May, 2000 at PUMC Hospital. Indications for surgery were symptomatic fibroids (20 cases), mainly pain or urine frequency; progressively increasing fibroid size (7 cases); coexistent adnexal pathology(26 cases) and infertility(21 cases). RESULTS: The number of fibroids of each patient varied from 1 to 4 with single fibroid of 62 cases (83.7%). The fibroids were located in anterior wall (30 cases), posterior wall (23 cases) and fundus (21 cases). A total of 93 fibroids were removed from these patients including 16 intramural fibroids and 77 subserous fibroids. The size of dominant fibroids ranged from 3 approximately 8 cm (mean 4.8 cm). In 19 cases (25.6%), the uterine wall was sutured in one layer. Mean duration of operation was 73 minutes and mean blood loss was 82 ml. Longer operating time and more blood loss were observed in patients with fibroids > or = 4 cm than those with fibroids < 4 cm. The difference was statistically significant ( P < 0.05). Mean postoperative hospital stay was 3.2 days and overall complication rate was 1.4%. The average postoperative follow-up period was 22 months (1 approximately 62 months). All the patients with symptoms showed remission of their complaints at 2-month follow-up. Recurrence of fibroid occurred in 1 case 1 year after initial operation and second laparoscopic myomectomy was given to her successfully. Five patients became pregnant. The pregnancy was uneventful and proceeded to selective caesarean section at term pregnancy in 4 cases. One miscarriage occured at 8 weeks in the 5th case. No adhesions at myomectomy site were found in these 5 patients. CONCLUSIONS: Our study suggests the feasibility of laparoscopic myomectomy in selected patients, which leads to effectiveness, low complication rate and satisfactory remission of symptoms. Further study on recurrence and fertility must be continued.

Adult↗
PubMed2000

Receptor subtype and dose dependence of dexmedetomidine-induced accumulation of [14C]glutamine in astrocytes suggests glial involvement in its hypnotic-sedative and anesthetic-sparing effects.

Dexmedetomidine, a selective alpha(2)-adrenergic agonist, increases accumulation of [14C]glutamine and its labeled metabolites in primary cultures of mouse astrocytes. The concentration dependence is biphasic and identical to that previously described for dexmedetomidine's effect on free cytosolic calcium concentration ([Ca(2+)](i)) in astrocytes, and both effects are exerted on the alpha(2A) subtype of the alpha(2) receptor, suggesting a Ca(2+)-mediated effect. The concentration corresponding to the most potent effect is similar to that with which dexmedetomidine exerts its anesthetic-sparing activity in vivo, and the second peak corresponds to its hypnotic-sedative effect. It is suggested that both effects may be caused by decreased glutamatergic neurotransmission, secondary to reduced availability of glutamine as a glutamate precursor in glutamatergic neurons.

Anesthetics↗
PubMed2000

Nucleotide sequence analyses of partial envgp46 gene of human T-lymphotropic virus type I from inhabitants of Fujian Province in Southeast China.

Partial sequences from the env(gp46) gene of two human T-lymphotropic virus type I (HTLV-I) isolates (LIN and WEN) obtained from inhabitants of Fujian Province in southeast China were analyzed. A phylogenetic tree was constructed from these sequence data and those of other known HTLV-I isolates from all over the world. Comparisons of the LIN and WEN nucleotide sequences with other HTLV-I isolates showed diversity ranging from 0.73 to 7.00% for LIN and from 0.87 to 7.00% for WEN. Sequences of isolates LIN, WEN, MT-2, TSP1, and CH were most closely related, and the phylogenetic tree showed that all belong to the widespread subtype A of the cosmopolitan group. These preliminary data indicate that HTLV-I isolates from Fujian Province, China are closely related to HTLV-I strains from Japan and the Caribbean.

Base Sequence↗
PubMed2000

Factors affecting improvement on the American Board of Surgery In-Training Exam (ABSITE).

BACKGROUND: American Board of Surgery In-Training Exam (ABSITE) performance can be used to assess resident knowledge and to evaluate surgical curriculum. To determine factors that lead to improved resident ABSITE performance, a prospective study was performed. MATERIALS AND METHODS: Thirty-four surgical residents in Program Years 2-5 completed pre- and a post-ABSITE questionnaires about their anxiety, self-efficacy, physical preparation, and academic preparation for the ABSITE. Department records were used to determine resident probationary status and conference attendance. A preliminary analysis of ABSITE scores indicated a significant improvement between 1998 and 1999 percentile scores (paired t = -2. 25, P = 0.03; m = 11.9, SD = 30.5, median = 7). An improvement in percentile rank score was calculated and used as the dependent variable in a stepwise regression analysis. The following served as independent variables: previous exam performance, anxiety, probationary status, amount of sleep before exam, confidence to score in the 25th and the 50th percentiles, and attendance at the three conferences rated most valuable by the residents. RESULTS: Results of the regression analysis demonstrate that all factors account for 62.3% of the variance in improvement scores. A stepwise analysis indicated that the combination of attendance (40.2%) and previous performance (18.3%) was significant in explaining 58.5% of the variance in improvement scores. Furthermore, Pearson's correlations indicated that probationary status (+.58, P = 0.001), anxiety (+0.53, P = 0.001), amount of study (+0.61, P = 0.001), past ABSITE performance (-0.60, P = 0.001), and conference attendance (+0. 56, P = 0.001) were correlated with ABSITE improvement. CONCLUSIONS: This study demonstrates that resident individual effort, past ABSITE performance, and academic conference attendance have led to resident ABSITE improvement.

Anxiety↗
PubMed2000

93G, a novel sporadic strain of hepatitis E virus in South China isolated by cell culture.

The nucleotide sequence of Hepatitis E virus (HEV) serous isolates (G-9 and G-20) from Guangzhou, South China, which has been reported previously, are divergent significantly from those of other reported HEV isolates. In order to investigate more extensively the Guangzhou isolate, the 93G strain was isolated from the faecal sample of the same individual as G-9 by A549 cell culture and identified immunologically and by molecular biological techniques. The results showed that strain 93G could be propagated in an A549 cell line causing cytopathic effects. The viral particles were aggregated by a specific antibody to HEV Chinese Xinjiang strain (87A) observed using immunoelectron microscopy and were similar morphologically to HEV from other sources. In this study, an indirect fluorescent antibody assay was first developed to examine HEV antigen in the infected cells, by immunofluorescence in the cytoplasm and on the surface membrane of the cells. The 58-kDa and 82-kDa native structural proteins of HEV were also identified in this study by Western blotting. The 93G genome showed high homology (93%) with G-9 previously reported but was also as divergent from the Burmese, Mexican, Chinese Xinjiang isolates and the recently reported US-1 isolate, as was G-9. The data presented indicate that 93G propagated in A549 cells, together with its related serum isolate G-9, represents another HEV strain circulating in China and is responsible for some sporadic hepatitis E infections.

Adult↗
PubMed2000

Tandem mass spectrometry studies of green tea catechins. Identification of three minor components in the polyphenolic extract of green tea.

Liquid chromatography/electrospray ionization mass and tandem mass spectrometry (MS/MS) techniques were used to identify two minor components and one new compound in the polyphenolic extract of green tea (Camellia sinensis). Identification and structure assignments were based on previously reported sub-structural features in the MS/MS product, precursor and neutral loss scans of reference samples. The structures of two minor components, related to the known green tea components epicatechin gallate (ECG, 5) and epigallocatechin gallate (EGCG, 6), are formed by methylation at the 3"-O-position of the gallic acid moiety. The new compound contained a gallic acid ester group, but had only one phenolic group in either the A- or B-ring, relative to the structure of 5. High-resolution mass measurements supported the empirical formula assigned to the new compounds. An important fragmentation for defining the position of methylation of the ester function involves ionization of the phenolic group at the 4"-position of the gallic acid, followed by elimination of the ester function as a neutral with concomitant formation of the m/z 169 ion. If the 4"-position is blocked by methylation, the formation of m/z 169 incorporating the gallic acid group would be blocked. Thus, the presence of an ion representing the ester group indicates a free 4"-phenol and the absence of this ion would signify the 4"-position as a site of methylation. The operation of this mechanism should be general and useful in assigning the site of methylation of any polyphenolic ester group in natural products. A similar conclusion can be drawn concerning alkylation or esterification of the 4'-position of the catechins, i. e. blocking the 4'-phenol would prevent formation of the m/z 125 ion common to all of the catechin compounds thus far examined. Therefore, mass spectral data are of considerable importance in deducing the sites of alkylation or esterification in the structures of the components of green tea.

Catechin↗
PubMed2000

New experimental evidence for somite resegmentation.

According to the concept of resegmentation, the boundaries of vertebrae are shifted one half a segment compared with somite boundaries. This theory has been experimentally confirmed by interspecific transplantations of single somites. Due to the difficulty of exactly orientating individual somites in the host embryo, the outcome and interpretations of these experiments have occasionally been questioned. This is especially true for the formation of neural arches, their processes, and the ribs. We reinvestigated the formation of vertebrae in the avian embryo by grafting one and one half somites from quail to chick embryos. This method eliminates the possibility of a wrong somite orientation in the host embryo. Results show that the vertebral body, the neural arch and its processes are made up of material of two adjacent somites. This is also true for the rib, with the exception of the costal head, which is formed by only one somite. Whereas in the proximal part of the costal body the chick and quail cell regions border on each other in the middle of the rib, in its distal part quail cells gradually begin to mix with chick cells. The intersegmental muscles and their skeletal attachments sites are formed from the same somite. These results support and complete the data of previous studies and confirm the resegmentation concept.

Animals↗
PubMed2000

The development of the avian vertebral column.

Segmentation of the paraxial mesoderm leads to somite formation. The underlying molecular mechanisms involve the oscillation of "clock-genes" like c-hairy-1 and lunatic fringe indicative of an implication of the Notch signaling pathway. The cranio-caudal polarity of each segment is already established in the cranial part of the segmental plate and accompanied by the expression of genes like Delta1, Mesp1, Mesp2, Ulicx-1, and EphA4 which are restricted to one half of the prospective somite. Dorsoventral compartmentalization of somites leads to the development of the dermomyotome and the sclerotome, the latter forming as a consequence of an epithelio-to-mesenchymal transition of the ventral part of the somite. The sclerotome cells express Pax-1 and Pax-9, which are induced by notochordal signals mediated by sonic hedgehog (Shh) and noggin. The craniocaudal somite compartmentalization that becomes visible in the sclerotomes is the prerequisite for the segmental pattern of the peripheral nervous system and the formation of the vertebrae and ribs, whose boundaries are shifted half a segment compared to the sclerotome boundaries. Sclerotome development is characterized by the formation of three subcompartments giving rise to different parts of the axial skeleton and ribs. The lateral sclerotome gives rise to the laminae and pedicles of the neural arches and to the ribs. Its development depends on signals from the notochord and the myotome. The ventral sclerotome giving rise to the vertebral bodies and intervertebral discs is made up of Pax-1 expressing cells that have invaded the perinotochordal space. The dorsal sclerotome is formed by cells that migrate from the dorso-medial angle of the sclerotome into the space between the roof plate of the neural tube and the dermis. These cells express the genes Msx1 and Msx2, which are induced by BMP-4 secreted from the roof plate, and they later form the dorsal part of the neural arch and the spinous process. The formation of the ventral and dorsal sclerotome requires directed migration of sclerotome cells. The regionalization of the paraxial mesoderm occurs by a combination of functionally Hox genes, the Hox code, and determines the segment identity. The development of the vertebral column is a consequence of a segment-specific balance between proliferation, apoptosis and differentiation of cells.

Animals↗
PubMed2000

Origin of the epaxial and hypaxial myotome in avian embryos.

The myotome originates from the dermomyotome. Controversy surrounds the location of myotome precursor cells within the dermomyotome and their segregation from the dermomyotome. Here we addressed the problem of myotome formation by labeling dermomyotome cells using the quail-chick marking technique. We carried out five series of transplantation and replaced: (1) the medial third, (2) the intermediate third, (3) the lateral third, (4) the cranial half, (5) the caudal half of a thoracic dermomyotome. The grafting procedures were performed in HH-stages 15-17 of quail and chick embryos. The chimeras were reincubated for 2 days up to HH-stages 24-25. All of the grafted parts contributed to the myotome. The epaxial myotome is derived from the medial third of the dermomyotome, while the hypaxial myotome is formed by both the intermediate and lateral third of the dermomyotome. Ep- and hypaxial myotome domains meet in the thickest part of the myotome that is situated in the middle of its ventrolateral axis. Myotome growth in the epaxial domain begins earlier than in the hypaxial domain. Cranial and caudal edges of the dermomyotome contribute equally to both the epaxial and hypaxial myotomes. The first born myotome cells are located in the lateral part of the epaxial myotome and development then proceedes in medial and lateral directions.

Animals↗
PubMed2000

Contribution of single somites to the skeleton and muscles of the occipital and cervical regions in avian embryos.

Controversy has surrounded the process of resegmentation of cervico-occipital somites. We have reinvestigated this topic by grafting single somites of quail embryos homotopically into chick embryos. Somites one to five contribute to the skull. Somites one and two contribute to the parasphenoid, which develops by direct ossification in a non-segmental fashion. All cartilaginous derivatives of the somites are segmental. Somite two forms a stripe of cells in the basioccipital, exoccipital and supraoccipital. Somites three to five give rise to the subsequent caudal parts of the basioccipital and exoccipital. Somite five forms the first motion segment including the occipital condyle, the cranial part of the atlas and the tip of the dens axis. Therefore, the border between head and neck is in the centre of somite five, and corresponds to the expression boundary of Choxb-3. Somite six forms the caudal part of the atlas and the cranial part of the axis. Somites two to eight all contribute to the cranio-cervical muscles with the exception of the Mm. rectus capitis dorsalis and ventralis and the M. biventer cervicis, which do not receive contributions from somite two. In contrast, the M. cucullaris capitis is exclusively formed by myogenic cells from somite two, which parallels its exclusive innervation by the accessory nerve. Our data confirm the segmental nature of the occiput, and show that resegmentation is a very regular process involving all except the four cranialmost somites. Except for somites one and two, all of the somites contribute to the muscles located at the appropriate levels.

Animals↗
PubMed2000

Indentification of venom proteins of spider S. huwena on two-dimensional electrophoresis gel by N-terminal microsequencing and mass spectrometric peptide mapping.

Venom proteins of the spider Selenocosmia huwena were separated by two-dimensional gel electrophoresis, with the separation in the first dimension on a wide range of immobilized pH (3-10) gradients. Over 300 protein spots were presented on a silver-stained 2D gel. The protein spots with molecular weight >10 kDa were analyzed, after electrotransferring to polyvinyldene difluoride (PVDF) membrane, by N-terminal microseqencing. Some of the silver-stained protein spots with molecular weight over 10 kDa were analyzed and identified by employing an improved procedure of mass spectrometric peptide mapping, including (1) in-gel reduction, alkylation, and enzymatic digestion; (2) extraction and desalting by using the pipette tip containing a small C18 microcolumn (Ziptip); and (3) direct MAIDI-TOF mass analysis and protein database searching. Several known toxins such as HWTX-I, HWTX-II, HWTX-IV, and SHL-I were identified and some new components were found among these protein spots.

Animals↗
PubMed2000

Dexmedetomidine-induced stimulation of glutamine oxidation in astrocytes: a possible mechanism for its neuroprotective activity.

Dexmedetomidine is a highly specific alpha2-adrenergic agonist, which is used clinically as an anesthetic adjuvant and in animal experiments has a neuroprotective effect during ischemia. The current study showed that dexmedetomidine enhances glutamine disposal by oxidative metabolism in astrocytes. This effect occurs at pharmacologically relevant concentrations. It is exerted on alpha2-adrenergic receptors and not on imidazoline-preferring sites, and it is large enough to reduce the availability of glutamine as a precursor of neurotoxic glutamate.

Adrenergic alpha-Agonists↗
PubMed2000

Dual origin and segmental organisation of the avian scapula.

Bones of the postcranial skeleton of higher vertebrates originate from either somitic mesoderm or somatopleural layer of the lateral plate mesoderm. Controversy surrounds the origin of the scapula, a major component of the shoulder girdle, with both somitic and lateral plate origins being proposed. Abnormal scapular development has been described in the naturally occurring undulated series of mouse mutants, which has implicated Pax1 in the formation of this bone. Here we addressed the development of the scapula, firstly, by analysing the relationship between Pax1 expression and chondrogenesis and, secondly, by determining the developmental origin of the scapula using chick quail chimeric analysis. We show the following. (1) The scapula develops in a rostral-to-caudal direction and overt chondrification is preceded by an accumulation of Pax1-expressing cells. (2) The scapular head and neck are of lateral plate mesodermal origin. (3) In contrast, the scapular blade is composed of somitic cells. (4) Unlike the Pax1-positive cells of the vertebral column, which are of sclerotomal origin, the Pax1-positive cells of the scapular blade originate from the dermomyotome. (5) Finally, we show that cells of the scapular blade are organised into spatially restricted domains along its rostrocaudal axis in the same order as the somites from which they originated. Our results imply that the scapular blade is an ossifying muscular insertion rather than an original skeletal element, and that the scapular head and neck are homologous to the 'true coracoid' of higher vertebrates.

Animals↗
PubMed2000

Sclerotomal origin of the ribs.

The somites of vertebrate embryos give rise to sclerotomes and dermomyotomes. The sclerotomes form the axial skeleton, whereas the dermomyotomes give rise to all trunk muscles and the dermis of the back. The ribs were thought to be ventral processes of the axial skeleton and therefore to be derived from the sclerotomes; however, recently a dermomyotomal origin of the distal rib (the costal shaft) was suggested, with only the proximal parts (head and neck of the rib) being of sclerotomal origin. We have re-investigated the development of the ribs in quail-chick chimeras and carried out three experimental series. (1) Single dermomyotomes and (2) single sclerotomes were grafted homotopically, and (3) the ectoderm overlying the unsegmented paraxial mesoderm was removed in the prospective thoracic region. We found that the cells of the dermomyotome gave rise to epaxial and hypaxial trunk muscles, dermis of the back and endothelial cells, but not to ribs. Cells of the sclerotome formed the axial skeleton and all parts of the ribs. Ablation of the ectoderm, which affects dermomyotome development, results in severe malformations of the ribs, probably due to disturbed interactions between dermomyotome and sclerotome. Our results strongly confirm the traditional view of the sclerotomal origin of the ribs.

Animals↗